'Risk of bias 2.0' tool

‘Risk of bias 2.0’ tool: This tool updates Cochrane’s current risk of bias assessment tool for RCTs. Those familiar with the existing tool will find many similarities, but the new tool includes some changes to the risk of bias domains and how they are assessed. The structure of the assessment process has been updated, and now uses a series of signalling questions to prompt authors in thinking through each domain (this structure is now used in several tools including ROBINS-I, see below, and QUADAS 2 tools). These questions lead authors to make decisions about the risk of bias for each domain, and there is now a more structured process to reach a judgement about the study’s overall risk of bias. Changes to the domains include some changes to terminology, the incorporation of domains specific to cross-over and cluster-randomized trials, and changes to the selective outcome reporting domain to focus only on the way outcomes are reported, while the issue of outcomes not reported will in future be assessed as an aspect of reporting bias. The assessment is now performed with a specific result in mind, and authors will also need to consider whether they are interested in the effect of starting and adhering to an intervention, or the effect of being assigned to receive an intervention (such as an invitation to participate in a health program). Click here for a webinar on the RoB 2.0 tool, or to read more about the tool.

Cochrane Scientific Committee recommendation: When officially released the RoB 2.0 tool will become mandatory for new reviews. It will not need to be applied retrospectively in updated reviews. The tool is currently undergoing some final refinement, and an implementation solution is required while the tool awaits integration into RevMan. Please await further announcements on its readiness for use. (Full statement)

Implementation statement

CSC members are not responsible for managing implementation of these recommendations which will require an implementation plan to ensure co-ordination for a smooth introduction. This will include launch, timescales and roll out strategy. Therefore, these statements do not signify immediate implementation.